We investigated the interference amplitude and phase characteristics of a multi-frequency sweeping interferometer with
sinusoidal phase modulating technique. A novel multi frequency sweeping light source that generated an interval and
center frequency variable frequency comb with a bandwidth of 14 nm was demonstrated. The interference phase and
amplitude distributions were investigated by observing the zeroth and first order interference signals. In addition, the
zeroth and first order interference phase variations caused by center frequency sweeping were measured.